Briquette mold pocket configuration

ABSTRACT

The mold faces of opposing briquetting rolls are arranged in Vshaped rows of rhomboid mold pockets.

Hendrickson et al.

BRIQUETTE MOLD POCKET CONFIGURATION Inventors: Luther G. Hendrickson. Churchill Borough; Dino Ravasio, McKeesport. both of Pa.

United States Steel Corporation, Pittsburgh. Pa.

Filed: June 28, 1974 Appl. No.: 483,997

Assignee:

[56] References Cited UNITED STATES PATENTS 1,882,160 10/1932 Paris 425/237 X 2.843.879 7/1958 Komarek et a1. 425/237 2.945.259 7/1960 Decker et a1. 425/237 X 2.958.902 11/1960 Decker et a1. 425/237 X Primary E.\'aminer--J. Howard Flint. Jr. Attorney, Agent, or Firm-William L. Krayer [57] ABSTRACT US. Cl 249/187; 425/237 Th6 mold faces of o b pposmg r1quettmg rolls are dl' Int. Cl B29d 7/14; 83% 3/00 ranged in V Shaped rows of rhomboid mold pockets. Field of Search 425/237; 249/187; 18/9, 1

18/10, 1 1 4 Claims, 4 Drawing Figures FLOW 0F EXCESS "REDUCED POWDER TENTEQ HAY 3|975 SHEET 1 [IF 2 1-HT F/a.

1 FLOW OF I axcsss ORE REDUCED &

FIG 2 DIREC 770m 0/-' SEGMENT TRAVEL D/REC 770 OF SEGMENT TRAVEL aw E 5 CUD H w MP FLOW OF 1 BRIQUETTEMOLD POCKET CONFIGURATION BACKGROUND OF THE INVENTION This invention relates to an improved pocket design for removable segments used in roll-type briquetting presses.

A conventional roll-type briquetting press includes a pair of power-driven rolls which are journaled on parallel axes, and whose circumferential faces contain a series of mating cavities. These mating cavities are contained in the removable segments that form the circumferential face of the briquetting roll. The rolls are usually held together by hydraulic pressure devices, whereby as they rotate, loose material fed between them is compacted within the cavities. For example, partially reduced particulate iron ore may be briquetted at temperaturesas high as l350F and under loads as great as 100,000 pounds per inch of effective roll width.

Difficulties have been encountered, however, in that the particulate reduced ore tends to flow at a significantly greater rate at the center of the face of the roll than it does at the outside of the face, i.e., near the stationary cheek plate usually employed to retain the ore in the area between rolls. One of the undesirable results of the uneven flow is an uneven distribution of density in the briquettes, which leads to a higher rate of physical degradation and a greater tendency to reoxidize.

The object of the present invention is to create an improved design for the cavities in the briquette-roll segments, which will provide a better flow of particulates from the center of the roll face to the outside, and thus produce a briquette with more uniform density.

Prior to the present invention, it has been known to employ briquetting rolls with angular cavities. See, for example, Decker et al. US. Pat. No. 2,958,902. The configuration shown in Decker, however, which places the mold segment at an angle carried across the entire face of the roll, is not able to create a flow of material .towards both sides of the mold face as ours is.

SUMMARY OF THE INVENTION We have designed our mold cavities in a rhomboid shape and have distributed them in rows of Vs across the face of the roll. Thus, some of the material which ordinarily would be compacted under great pressure at the point of the V will find paths of less resistance upward and outward on both sides thereof. Our invention includes a mold segment for use in a tandem roll briquette machine comprising a body portion adapted for inclusion on the periphery of a mold roll, and a plurality of mold pockets arranged in a V-formation extending from a central vertical land area. Our invention will be further described with respect to the accompanying drawings.

IN THE DRAWINGS:

FIG. 1 is a top plan or face view of a conventionally designed briquette segment.

FIG. 2 is a vertical section view of the conventional briquette segment shown in FIG. 1, indicating the direction of segment travel.

FIG. 3 is a face view of a briquette segment constructed in accordance with our invention.

FIG. 4 is a vertical section view of the mounted roll segments with the cheekplate in position.

Referring to FIG. 1, the face of a conventional segment typically has several whole mold pockets or cavities 1, several half-pockets 2, land areas 3 separating the pockets, and side or ledge areas 4.

As shown in FIG. 1, the flow of excess partially reduced powder during the briquetting operation will be toward the uppermost portion of the cavity since that portion of the cavity is the last to undergo compaction.

FIG. 2 shows a section of a segment as it would appear near the nip of the rolls, i.e., when it is almost contacting another opposing segment on the opposite roll. The base area 5 of the segment fits into a recess in the star wheel usually forming the roll. The flow of excess" powder in the conventional configuration is vertical. This phenomenon has been confirmed by the fact that densities, determined from sectioned briquettes produced with this design, were slightly greater in the upper half of the briquettes.

FIG. 3 is a top or face plan view of our segment showing the parallelogram or rhomboid shape of our pockets. Whole pockets 6 and half pockets 7 are designed in a V-shape, as outlined by V-shaped land areas 8. As indicated, the partially reduced powder tends to flow in a path parallel to the ascending land areas, thus distributing it in a more even density in the entire volume of the pocket.

FIG. 4 is a more or less diagrammatic side view of a tandem briquette roll machine. It shows rolls 9 and 10 having peripheral mold pockets 11 (in segments not illustrated) mating at area 12 near the nip of the rolls, and cheekplate 13 designed to retain material such as reduced iron ore powder between the rolls. A screw feeder or other feeding device is placed directly above this assembly to force the powder into the nip of the rolls. Because of the poor flow near the cheekplates and powder loss which occurs in the space between the cheekplate l3 and the pockets l1, densities of the briquettes in this area are lower than in other areas of the briquette. Rolls 9 and 10 may be star wheels or any other device capable of holding pocket segments.

Our invention utilizes the flow of reduced powder described in such a manner that excess reduced powder will be directed to theside portion of the cavity rather than the center or top portion. In effect, the side portion of the cavity, i.e., that nearest the cheekplate, is provided with sufficient reduced powder to replace that which is lost through cheekplate leakage and to evenly distribute the pressure on the powder. The delay in compacting of the reduced powder at the side portion of the cavity provided by this design will thus ensure that sufficient time is provided for flow of excess reduced powder from the lower portion of the cavity. It is the placement of the cavity at an inclined angle to the horizontal, i.e., the herringbone design, which provides this change of powder flow during the briquetting step. This same operation is repeated as each cavity in the circumferential face of the briquetting roll rotates downward into the briquetting zone.

From the foregoing description, it is seen that our invention affords a simple, effective means of achieving relatively uniform density in briquettes, by creating an upward and outward flow pattern of partially reduced iron ore powder within the briquette roll cavity through the use of mold pockets in a herringbone configuration.

The angles of the Vs may vary from about 10 to about 30. Land areas are generally about /a inch wide; depending on the dimensions of the overall machine,

land areas of 1/16 to inch may be desirable. For best results on reduced iron ore, the pockets should have depths at their deepest points of about 0.350 to 0.475 inches. We have found that four whole pockets and four half-pockets form a convenient pattern compatible with commercial segment shapes for placement on currently commercial star wheels. Other configurations may be used, but the most efficient design will minirnize the frequency of segment abutments cut diagonally through the pockets. A plurality of pockets should be formed with a symmetrical V-shaped design.

Persons skilled in the art may recognize that conventional segment design may not be essential; our invention includes a method of making briquettes comprising feeding particulate material such as reduced iron ore into the nip of two tangential rolls having mating peripheral mold pockets, said pockets being disposed in a V-formation extending from a central land area and compacting said ore in the pockets between said rolls.

We do not intend to be restricted to the particular embodiments used for illustration herein. Our invention may be otherwise variously practiced within the scope of the following claims.

We claim:

l. A mold segment for use in a tandem roll briquette machine comprising a body portion adapted for inclusion on the periphery of a mold roll, and a plurality of mold pockets arranged in a V-formation extending from a central vertical land area.

2. Segment of claim 1 in which the pocket angles are from about 10 to about 30 from the horizontal.

3. Segment of claim 1 in which the land areas are about l/l6 to about A inch wide.

4. A mold segment comprising a body portion adapted for inclusion on the periphery of a mold roll and at least two rhomboid-shaped mold pockets in symmetrical V-formation relation with respect to a vertical land area. 

1. A mold segment for use in a tandem roll briquette machine comprising a body portion adapted for inclusion on the periphery of a mold roll, and a plurality of mold pockets arranged in a Vformation extending from a central vertical land area.
 2. Segment of claim 1 in which the pocket angles are from about 10* to about 30* from the horizontal.
 3. Segment of claim 1 in which the land areas are about 1/16 to about 1/4 inch wide.
 4. A mold segment comprising a body portion adapted for inclusion on the periphery of a mold roll and at least two rhomboid-shaped mold pockets in symmetrical V-formation relation with respect to a vertical land area. 